What Happened to Ancient Megafauna?
nautil.us
What Happened to Ancient Megafauna?
1–10 of 103 posts
Re: What Happened to Ancient Megafauna?
#2This is not about assigning blame, says Svenning. “People who lived thousands of years ago never had access to the full picture. These things took place across long time scales and big spatial scales over which no one had an overview; whatever people did, it was difficult to see the consequences. Plus, of course, people just had to survive the best they could.” - lol even
Re: What Happened to Ancient Megafauna?
#3> Defined as large-bodied terrestrial mammals with a mean adult body mass of 2,200 pounds or more, today’s remaining megaherbivores comprise the likes of elephants, rhinoceroses, giraffes, and hippopotamuses.
Was there difference in hunter-gatherers in europe/asia/americas compared to africa? Why hadn't the ancient elephants, giraffes, etc been hunted to extinction?
> I think work over the past few decades has rather convincingly demonstrated that humans had a pretty substantial part in the extinction
A substantial part in the extinction? What does that mean? The extermination of the buffalo in the US required industrial scale resources ( guns, railroads, etc ) along with the migration of millions of europeans and habitat loss ( via farming ). It was a conscious and intentional effort. Are they claiming something similar happened throughout much of europe, asia and americas more than 50,000 year ago?
> “When we restore forests, we can’t just think about the trees,” he says. “We must think about the animals that belong there.”
This. The most devastating blow for the buffalo, wolves, bears, etc was habitat loss. It was ultimately what did them in. Did ancient hunter-gatherers alter their environment to such a degree to wipe out herds of giant animals from entire continents?
I have a hard time believing that hunter gathers in tiny tribes traveling on foot with primitive weapons could have hunted and wiped out entire species of large animals from continents. I wish they would give more specifics.
Re: What Happened to Ancient Megafauna?
#4I'm still digesting the full paper [1] but it looks like the gist is that when you put all the previously published data together, the timing of megafauna extinction statistically lines up with human arrival better than climate change.
The most important pieces of evidence they seem to look at is fungal spores in fossilized poop and sedimentary ancient DNA:
> Further, other studies show contrasting patterns. For example, a sedimentary ancient DNA (sedaDNA) study from the Yukon shows strong megafauna decline between 21 and 14,500 years ago, prior to the loss of the mammoth steppe biome and the Younger Dryas. In addition, as already mentioned, many extinct megafauna species have last occurrences in the Early or even Middle Holocene, that is, during the relatively stable climate of the Holocene, meaning that a climatic cause for their extinction is unlikely given their previous survival through numerous, massive climatic shifts throughout the Pleistocene, including long and warm interglacial periods.
> An increasing number of studies look at local and regional dynamics in the overall abundance of large herbivores at high spatiotemporal resolution using dung-associated fungal spores. Many of these are able to pinpoint declines to timeframes where the climate was stable, for example, North America ~14–13,000 years ago, prior to the Younger Dryas cooling, and 41,000 years ago in Australia at a time of no substantial climate change
These techniques are still very new and they're so sensitive that they should be taken with a grain of salt, sedaDNA especially since it amplifies tiny snippets of DNA found in permafrost. We assume permafrost behaves like an annually laminated sediment but that's controversial and archaeology/paleontology have had plenty of problems before with DNA snippets and contamination.
[1] https://www.cambridge.org/core/journals/cambridge-prisms-ext...
Re: What Happened to Ancient Megafauna?
#5This guy (https://www.youtube.com/@Antonio_Zamora) makes a very solid argument that in the Younger Dryas a meteorite impactor hit the ice sheet over the Great Lakes, sending huge ice chunks flying that created elliptical craters that then quickly refilled that are called the Carolina Bays, and which are ubiquitous in the South East, and which point back at the impact point(s) (I think he says there were two impact points) in Michigan. The amount of energy delivered by all those ice chunks seems to have been several megatons (of TNT) per square mile. Enough chunks were ejected, and carolina bays formed, to have likely caused an extinction event.
Re: What Happened to Ancient Megafauna?
#6[flagged]
Re: What Happened to Ancient Megafauna?
#7The linked nautil.us article is a one sided poor summary of what is still an ongoing debate with strong beliefs on either side.
Two people are quoted:
* Jens-Christian Svenning, director of the Danish National Research Foundation’s Center for Ecological Dynamics in a Novel Biosphere at Aarhus University. He’s also the lead author on a recent paper published in Cambridge Prisms: Extinction that argues it was not climate change but rather human hunting that caused the extinction of most megaherbivores over the past 50,000 years.
and
* Felisa Smith, a conservation paleoecologist and professor at the University of New Mexico, believes that the human impact on megafauna extinction is no longer up for debate. “I think work over the past few decades has rather convincingly demonstrated that humans had a pretty substantial part in the extinction,” says Smith.
and ... no other views are given.
This, currently, isn't a slam dunk for one side, there are strong voices on the other side who can cite examples where humans certainly ate megafauna but not, apparently, enough to wipe them out and also point at concurrent pockets (eg: Tasmania) where there were megafauna, as yet no humans, and still the megafauna died out.
Re: What Happened to Ancient Megafauna?
#8This guy ( https://www.youtube.com/@Antonio_Zamora ) makes a very solid argument that in the Younger Dryas a meteorite impactor hit the ice sheet over the Great Lakes, sending huge ice chunks flying that created elliptical craters that then quickly refilled that are called the Carolina Bays, and which are ubiquitous in the South East, and which point back at the impact point(s) (I think he says there were two impact…
There's a real danger in getting misinformation from YouTube channels. The Younger Dryas Impact Hypothesis has been extensively refuted multiple times. The latest such paper (https://doi.org/10.1016/j.earscirev.2023.104502) is pretty exhaustive in exploring the history of these ideas and how they fall short.
Re: What Happened to Ancient Megafauna?
#9> Defined as large-bodied terrestrial mammals with a mean adult body mass of 2,200 pounds or more, today’s remaining megaherbivores comprise the likes of elephants, rhinoceroses, giraffes, and hippopotamuses. Was there difference in hunter-gatherers in europe/asia/americas compared to africa? Why hadn't the ancient elephants, giraffes, etc been hunted to extinction? > I think work over the past few decades has rather…
> Was there difference in hunter-gatherers in europe/asia/americas compared to africa? Why hadn't the ancient elephants, giraffes, etc been hunted to extinction?
One theory is that they gradually adapted as humans developed.
Once humans spread out to other continents the change was too rapid for the megafauna on those continents to adapt.
Re: What Happened to Ancient Megafauna?
#10> Defined as large-bodied terrestrial mammals with a mean adult body mass of 2,200 pounds or more, today’s remaining megaherbivores comprise the likes of elephants, rhinoceroses, giraffes, and hippopotamuses. Was there difference in hunter-gatherers in europe/asia/americas compared to africa? Why hadn't the ancient elephants, giraffes, etc been hunted to extinction? > I think work over the past few decades has rather…
> Was there difference in hunter-gatherers in europe/asia/americas compared to africa? Why hadn't the ancient elephants, giraffes, etc been hunted to extinction?
Consider that African megafauna have co-existed with early hominids and eventually humans for millions of years. They may have simply adapted to human predation successfully enough to survive, as one factor.
Whereas in North America and elsewhere you have the sudden (on the evolutionary time scale) arrival of Homo Sapiens who are likely already very skilled and advanced hunters among a population of prey animals that have never experienced such a predator.
It’s also possible that in tandem, climate change was less severe in Africa than elsewhere over the last 50k years.